Cannot modify the Druid database if unreachable.

### Bug description

We recently migrated our data from Druid to Databricks. Since Druid is no longer in use, I want to disable it in SQL Lab. However, unchecking `Expose database in SQL Lab` results below error.

`An error occurred while fetching databases: "Connection failed, please check your connection settings"
`

It is possible it act like this for all database types.

### Screenshots/recordings

_No response_

### Superset version

6.1.0

### Python version

3.9

### Node version

16

### Browser

Chrome

### Additional context

_No response_

### Checklist

- [x] I have searched Superset docs and Slack and didn't find a solution to my problem.
- [x] I have searched the GitHub issue tracker and didn't find a similar bug report.
- [x] I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.

Start with the SQL Lab database settings flow and reproduce the failure by trying to disable an unreachable Druid connection. Trace where the “Connection failed” response is handled, then verify that `Expose database in SQL Lab` can be unchecked without requiring the database connection to succeed.

Written by the indexing model from the issue text.